C语言故事生成程序字符串打印异常问题求助

你的代码出现无空格拼接字符串和**(NULL)占位符**的问题，核心是以下几个错误导致的：

1. 字符串数组元素缺少分隔逗号 #

所有字符串数组（bird、color、car等）里的元素之间没加逗号，C语言会自动把相邻字符串常量拼接成一个长串，导致数组实际有效元素数量远少于ARRAY_SIZE，剩余位置被初始化为NULL。当rand()取到这些NULL位置时，就会显示(NULL)，而拼接后的长串会造成无空格填充的问题。

修复方法：给每个数组元素末尾加上逗号（最后一个元素可省略，但建议统一格式），示例：

char* bird[ARRAY_SIZE]={
    "hawk", //0
    "eagle", //1
    "pigeon", //2
    "sparrow", //3
    "cardinal", //4
    "raven", //5
    "pelican" //6
};

所有类似的字符串数组都需要做此修改。

2. 输入处理逻辑错误 #

你先用fgets()读取用户输入，紧接着又用gets()覆盖内容，这会引发三个问题：

• fgets()读取的内容直接被丢弃，gets()会读取fgets()留下的换行符，导致answers[i]变成空字符串
• gets()是不安全函数，存在缓冲区溢出风险
• 若answers[i]为空，strlen(answers[i])-1会访问数组越界，触发未定义行为

修复方法：删掉gets()调用，仅保留fgets()，并处理掉fgets()读取到的换行符：

for(int i=0; i<ARRAY_SIZE; i++){
    printf("%s\n", questions[i]);
    if(fgets(answers[i],MAX_LEN,stdin) == NULL){
        fprintf(stderr, "输入错误\n");
        return 1;
    }
    // 去除换行符
    size_t len = strlen(answers[i]);
    if(len > 0 && answers[i][len-1] == '\n'){
        answers[i][len-1] = '\0';
    }
}

3. 拼写错误 #

故事文本里的on thier way是拼写错误，需改为on their way，避免输出错误内容。

修复后的完整代码 #

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define MAX_LEN 64
#define ARRAY_SIZE 7

/*This story will go something like this:
    Flying through the sky, a <bird> looks down upon <current city name>
    and spots <name>. <name> is <age> years old and is studying to
    become a <career title>. <name> is on their way to <hometown name>
    to visit their <number> family members. As <name> packs their stuff 
    into a <color> <car>, their pet <favorite animal>, <pet name> gets in the vehicle,
    and starts to <animal sounds>. <name> pets <pet name> and gets in the vehicle.
    <name> starts the car and turns the radio up. <name> and <pet name> listens to <song>
    for the whole <number> hour long trip. Once <name> and <pet name> arrived, <ending>.*/
int main(){

    char* questions[ARRAY_SIZE]={
        "what is your name?", //0
        "what is your favorite animal?", //1
        "where were you born?", //2
        "how old are you?", //3
        "where do you currently live?", //4
        "what do you want your future career to be?", //5
        "what is your pet's name?", //6
    };

    const int NAME = 0, ANIMAL = 1, BIRTHPLACE = 2, AGE = 3, HOME = 4, CAREER = 5, PET_NAME = 6;

    char* bird[ARRAY_SIZE]={
        "hawk", //0
        "eagle", //1
        "pigeon", //2
        "sparrow", //3
        "cardinal", //4
        "raven", //5
        "pelican" //6
    };

    char* color[ARRAY_SIZE]={
        "red", //0
        "orange", //1
        "yellow", //2
        "green", //3
        "blue", //4
        "indigo", //5
        "violet" //6
    };

    char* car[ARRAY_SIZE]={
        "Hyundai Tucson", //0
        "Ford Mustang", //1
        "Dodge Charger", //2
        "Ford Focus", //3
        "Chevrolet Tahoe", //4
        "Subaru Outback", //5
        "Buick Park Avenue" //6
    };

    char* sounds[ARRAY_SIZE]={
        "barking", //0
        "meowing", //1
        "cooing", //2
        "roaring", //3
        "growling", //4
        "cawing", //5
        "squeaking" //6
    };

    char* song[ARRAY_SIZE]={
        "\"don't stop believin'\" by journey", //0
        "\"bohemian rhapsody\" by queen", //1
        "\"under the bridge\" by red hot chili peppers", //2
        "\"logan circle\" by the wonder years", //3
        "\"shout at the devil\" by motley crue", //4
        "\"do re mi\" by blackbear", //5
        "\"the time (dirty bit)\" by the black eyed peas" //6
    };

    char* number[ARRAY_SIZE]={
        "one", //0
        "two", //1
        "three", //2
        "four", //3
        "five", //4
        "six", //5
        "seven" //6
    };

    char* endings[ARRAY_SIZE]={
        "they all had a bonfire", //0
        "they all watched a movie", //1
        "they all went out to eat", //2
        "they all ate dinner at home", //3
        "they all watched the stars at night", //4
        "they all set off fireworks", //5
        "they all went to bed to continue visiting in the morning" //6
    };

    char answers[ARRAY_SIZE][MAX_LEN];

    for(int i=0; i<ARRAY_SIZE; i++){
        printf("%s\n", questions[i]);
        if(fgets(answers[i],MAX_LEN,stdin) == NULL){
            fprintf(stderr, "输入错误\n");
            return 1;
        }
        size_t len = strlen(answers[i]);
        if(len > 0 && answers[i][len-1] == '\n'){
            answers[i][len-1] = '\0';
        }
    }
    srand(time(NULL));

    printf("=================================================================\n");
    printf("Flying through the sky, a %s looks down upon %s\n",bird[rand()%ARRAY_SIZE], answers[HOME]);
    printf("and spots %s. %s is %s years old and is studying to\n",answers[NAME], answers[NAME], answers[AGE]);
    printf("become a %s. %s is on their way to %s\n",answers[CAREER], answers[NAME], answers[BIRTHPLACE]);
    printf("to visit their %s family members. As %s packs their stuff\n",number[rand()%ARRAY_SIZE], answers[NAME]); 
    printf("into a %s %s, their pet %s, %s gets in the vehicle,\n",color[rand()%ARRAY_SIZE], car[rand()%ARRAY_SIZE], answers[ANIMAL], answers[PET_NAME]);
    printf("and starts to %s. %s pets %s and gets in the vehicle.\n",sounds[rand()%ARRAY_SIZE], answers[NAME], answers[PET_NAME]);
    printf("%s starts the car and turns the radio up. %s and %s listens to %s\n",answers[NAME], answers[NAME], answers[PET_NAME], song[rand()%ARRAY_SIZE]);
    printf("for the whole %s hour long trip. Once %s and %s arrived, %s.",number[rand()%ARRAY_SIZE], answers[NAME], answers[PET_NAME], endings[rand()%ARRAY_SIZE]);

    return 0;
}

内容的提问来源于stack exchange，提问作者BluemanDoug